1. Field of the Invention
The invention relates to a belt-braking device for safety belt systems, especially for motor vehicles, and more particularly refers to a new and improved safety belt system in which a belt-brake which is activated by the belt pull, is arranged after an automatic locking device, and serves to eliminate the film-spool effect at the belt lock roller of the automatic device.
2. Description of the Prior Art
In safety belt systems, after the locking of the belt in an automatic roll-up device, there are approximately 50 to 100 mm of belt band which can still be pulled out ffrom the belt portion rolled up in the automatic roll-up device, due to a film-spool effect at the roller. By sequentally arranging a holding device which arrests the belt after a short path, that is, almost immediately, this undesired film-spool effect is avoided.
There are devices known provided with such belt braking provisions, in which, when the belt brake is activated, the belt band is mechanically pressed between suitably shaped clamping jaws and thereby prevented from being pulled out any further. During this clamping, the fabric of the belt is strongly squeezed in small local areas and thereby damaged, so that the belt is unable with the required safety factor to accept the forces imposed by a crash. This unreliability factor is further aggravated by the fact that this clamping action occurs not only at an accident, but also during sharp braking when the belt brake is activated and moves into the clamping position. Severe damage to the belt results from the repeated clamping actions during its normal lifetime. The danger exists under these conditions that the belt will break in the case of an accident, a fact proven by suitable experiments. Therefore, in practice, these known belt-braking devices were not used.